This invention relates to compositions and methods for the introduction of a formulated nucleic acid into a cell for the expression of a peptide or polypeptide. It is useful for in vitro transfections and in vivo for gene therapy, for among other things administration of therapeutic proteins, polypeptides and peptides and for vaccination.
Non-viral administration of nucleic acid in vivo has been accomplished by a variety of methods. These include lipofectin/liposome fusion: Proc. Natl. Acad. Sci., Volume 84, pp. 7413-7417 (1993); polylysine condensation with and without adenovirus enhancement: Human Gene Therapy, Volume 3, pp. 147-154 (1992); and transferrin:transferrin receptor delivery of nucleic acid to cells: Proc. Natl. Acad. Sci., Volume 87, pp. 3410-3414 (1990). The use of a specific composition consisting of polyacrylic acid has been disclosed in WO 94/24983. Naked DNA has been administered as disclosed in WO 90/11092.
An important goal of gene therapy, as an initial step in the process of ultimately obtaining expression of a product encoded by a nucleic acid, is to effect the uptake of nucleic acid by cells. Uptake of nucleic acid by cells is dependent on a number of factors, one of which is the length of time during which a nucleic acid is in proximity to a cellular surface. For instance, after intramuscular (i.m.) administration of plasmid DNA in buffer, a marked reduction in gene expression is observed if the muscle is massaged, presumably due to DNA leakage out of the muscle either directly or via lymphatic vessels (Human Gene Therapy 4:151-159; 1993). Accordingly, it would be desirable to formulate nucleic acids with compounds which would retard the rate at which nucleic acids diffuse or are carried away from a site at which cellular uptake of the nucleic acid is desired. Further, these compounds would be suitable for administration to an organism by means such as injection while maintaining or regaining the physical characteristics necessary to increase cellular uptake of nucleic acids.